U.S. Sen. Bernie Sanders endorsed Zohran Mamdani on Tuesday, giving the progressive New York City mayoral candidate a boost as he challenges establishment forces in the 2025 Democratic primary.

Mamdani, a Queens assemblyman, welcomed the endorsement with praise for the Vermont senator's influence on his political vision.

"As for so many across this country, Bernie Sanders has been the single most influential political figure in my life," Mamdani said in a statement. "At the core of our vision for New York is the belief that only through bold leadership that puts the needs of the 99% over the power of the 1% can we defeat the rise of oligarchy and authoritarianism. Make no mistake: oligarchy is on the ballot. Andrew Cuomo is the candidate of a billionaire class that is suffocating our democracy and forcing the working class out of our city. As mayor, I will strive each and every day to live up to Senator Sanders' example, making New York affordable and hopefully making Brooklyn's own proud."

Sanders, in a post on X, framed Mamdani as the best choice for mayor amid a perilous political moment.

“At this dangerous moment in history, status quo politics isn’t good enough. We need new leadership that is prepared to stand up to powerful corporate interests & fight for the working class,” the post reads. “@ZohranKMamdani is providing that vision. He is the best choice for NYC mayor.”

Sanders has been on a nationwide crusade to lure voters back to the Democratic party after Republican wins last November and Donald Trump’s reelection to the presidency.

In Astoria, Queens on Tuesday, Mamdani referred to Sanders as “someone who continues to inspire New Yorkers across the five boroughs about the possibility of our democracy being something more than that which is bought and paid for by Republican billionaires.”

Sanders has never weighed into a Democratic mayoral primary contest — although, in 2017, he did endorse former Mayor Bill de Blasio’s reelection bid.

Mamdani says the endorsement will expand his reach.

“He’s someone that, when he ran for president in 2016, by the time that primary got to New York City, when his campaign was effectively not campaigning here across the five boroughs, he won 42% of the Democratic primary vote on Staten Island,” he said.

While the Democratic Socialists share a host of key policy ideas, like taxing the rich, both men have a history of taking on the establishment.

Flashback to 2016, when then-presidential candidate Bernie Sanders dominated the small donor donation game over rival and eventual Democratic presidential nominee Hilary Clinton, who benefited heavily from Super PAC cash.

Although Sanders attracted massive support, he slammed the national Democratic Party for failing to support left-of-center candidates like himself.

He criticized big money in politics, closed primary elections in states like New York and called for a reorganization of party leadership.

“So much of New Yorkers’ frustrations with the policies of the past is that we have been unable to learn from any of those same lessons,” Mamdani said.

Rep. Alexandria Ocasio-Cortez, D-N.Y., a leading progressive voice in Congress, has also endorsed Mamdani.

The Democratic primary is expected to be a test of strength between progressive challengers and more moderate or establishment-backed candidates, including Cuomo, a former governer seeking a political comeback.

Cuomo’s campaign and supportive Super PACs are pouring campaign cash into many ads criticizing Mamdani over his short tenure in Albany and slim legislature record. The two-term assemblyman has sponsored just three bills signed into law.

Mamdani says his campaign is striking fear in Team Andrew Cuomo.

“I don’t think Michael Bloomberg would be taking a selfie voting for Andrew Cuomo if he wasn’t afraid,” he said. “With one week to go, with a volunteer team with more than 46,000 people, a volunteer team that has knocked on more than 1.1 million doors across the five boroughs.”

In the mayoral primary, Mamdani has attracted the greatest number of total donors out of all the major candidates, maxing out of fundraising and ability to attract public matching dollars.

Sanders' backing comes on the heels of a slew of cross-endorsements for and from Mamdani in an attempt to ice out frontrunner Cuomo. Michael Blake and Brad Lander, two other Democratic mayoral candidates, are urging their supporters to use ranked-choice voting strategically by ranking Mamdani second.

Polls in recent weeks have shown that Cuomo's lead over Mamdani has narrowed considerably.

Sanders also endorsed City Councilman Justin Brannan in his bid for city comptroller.

“Bernie’s a legend. Brooklyn born, he’s been fighting for working people and calling out corruption long before it was cool,” Brannan said in a post on X. “I was proud to be his delegate in 2020, and I’m even prouder to have his support today.”

Brannan, a Democrat, is running against Manhattan Borough President Mark Levine and Brooklyn state Sen. Kevin Parker for the position.